A storage system using a remotely operated vehicle for picking up storage bins from a bin storing structure is known. A detailed description of a relevant prior art storage system is given in WO 98/49075. Further, details of a prior art vehicle being suitable for such a storage system is disclosed in Norwegian patent NO317366. More specifically the prior art storage system comprises a three dimensional storage grid containing storage bins that are stacked on top of each other to a certain height. The storage grid is normally constructed as aluminium columns interconnected by top rails. A number of remotely operated vehicles, or robots, are arranged on the top rails. Each vehicle is equipped with a lift for picking up, carrying, and placing bins that are stored inside the storage grid.
Such a prior art storage system art and prior art robot is illustrated in FIGS. 1 and 2, respectively. The storage system 3 comprises a robot 1 which is arranged to move on dedicated supporting rails 13 and to receive a storage bin 2 from a storage column 8 within a bin storing grid 15. The storage system 3 includes a plurality of such robots 1 and a dedicated bin lift device 50, the latter being arranged to receive a storage bin 2 from the robot 1 at the top level of the bin storing grid 15 and to convey the storage bin 2 down in a vertical direction to a delivery station 60.
However, the prior art robot 1 of the storage system shown in both FIG. 1 and FIG. 2 suffers from several important disadvantageous during their operation. Firstly, the particular design of the robot prevents access to all off the available storage columns in the storage system. Furthermore, this particular design may cause an undesirable high torque during lifting and transportation of storage bins, thereby creating potential instability problems, as well as a clear limitation of the robots maximum handling weight. An additional disadvantage caused by the prior art robot design is the fact that only one particular bin and one particular bin height may be accepted for each type of robot in order to ensure adequate stability. Finally, the presence of an integrated yoke/overhang in the upper part of the section receiving the storage bin necessitates an undesired speed reduction at the final stage of the lifting process performed by the yoke suspended vehicle lifting device.